Thermal analysis is a technique that measures a certain physical property of a sample as a function of temperature while varying the sample in temperature according to a predetermined program. As temperature changes, a sample undergoes a phase change such as melting, vaporization, etc. and a shape change such as expansion, contraction, etc. A change of state of a sample is widely and further deeply analyzed by preserving data of electromagnetic waves, such as a sample picture, etc. before and after the phase change or the shape change, from a sample to analyze the same together with data of thermal analysis.
In a conventional thermal analysis equipment, sample pictures are stored in a medium such as video tape recorder, etc. for continuous recording, and no specific consideration is taken in relating storage capacity and results of thermal analysis with each other (for example, see JP-A-8-327573 (page 2 to 3, FIG. 1)).